Serum and Cervical Flushing Fluid Eicosapentaenoic Acid Levels in Patients With Unexplained Infertility Versus Healthy Controls

ABSTRACT To compare the levels of eicosapentaenoic acid (EPA) in venous blood and cervical flushing fluid between patients with unexplained infertility and a control group, marking the first investigation of its kind in the literature. Recep Tayyip Erdogan University Education and Research Hospital‐based cross‐sectional study. This study was conducted with a total of 66 women (35 with unexplained infertility and 31 healthy controls) between 20 and 45 who attended the outpatient gynecology clinic between January 2023 and January 2024. Samples for EPA were collected in the midluteal phase and stored at −80°C, analyzed using EPA's ELISA kits. Baseline demographic and hormonal parameters were similar between the unexplained infertility and control groups. Serum EPA levels were lower in the unexplained infertility group, but the difference was not statistically significant. In contrast, cervical flushing fluid EPA concentrations were significantly reduced in women with unexplained infertility ( p < 0.001). No correlation was observed between serum and cervical EPA levels (Spearman's ρ = 0.13, p = 0.28). In multivariate analysis, unexplained infertility independently predicted lower cervical EPA concentrations, explaining approximately one‐third of the total variance ( R 2 = 34.3%). Cervical flushing fluid EPA levels were significantly lower in the unexplained infertility group compared to the control group. These findings suggest that local anti‐inflammatory lipid imbalance in the cervical microenvironment may contribute to fertility impairment. Further studies are needed to clarify the potential role of EPA as a biomarker or therapeutic target in reproductive disorders.